The present invention relates to an electrophotographic copier, facsimile machine, laser printer or similar equipment which uses an electrophotographic procedure. More particularly, the present invention is concerned with a device installed in such equipment for collecting toner particles which remain on a photoconductive element, or image carrier, after imagewise transfer.
In equipment of the type described, an electrostatic latent image representative of an original image to be recorded is formed on a photoconductive element. The latent image is developed by a toner which is fed from a developing unit to become a toner image. After the toner image has been transferred from the photoconductive element to a paper sheet, the toner remaining on the photoconductive element is removed by a fur brush and a cleaning blade which are held in contact with the photoconductive element. The removed toner is collected in a toner tank. It has been customary to collect the toner in the toner tank through an opening which is formed through a bottom portion of the tank. A collecting roller having a polygonal cross-section and a collecting blade are disposed in the opening in contact with each other. As the collecting roller is driven in a rotary motion in a predetermined direction, it urges the free end or tip of the collecting blade with the apexes of the polygonal cross-section to thereby cause the blade into a periodical oscillatory motion. The collecting blade being so moved forces the toner into the toner tank. When the toner being collected fills up the toner tank, a sensor mounted on the top of the toner tank is actuated by the toner to show that the tank is full. In this kind of prior art toner collecting arrangement, since the opening for collecting the toner is located in close proximity to the bottom of the toner tank and since the collecting roller and collecting blade are disposed in this opening, the load acting on the blade, i.e., on the roller increases with the amount of toner in the tank. Therefore, it is necessary to sequentially increase the output force of a drive source which drives the collecting roller. When the load acting on the roller sequentially increases from the start of a collecting operation until the toner tank becomes full as stated above, it effects the driving system and thereby renders the control thereover difficult. The influence of the varying load on the driving system appears as jitters in a resulting image to lower the image quality to a noticeable extent.